It's Time to SUPERSIZE Moby - MoTech 6.2L LS Jeep Motor Swap
- Thread starter CarsonCindy
- Start date
LiveFree0rDie
New member
Roger that, thanks.
LFoD
LFoD
Okay, since picking Moby up back in December, Cindy and I have racked up about 18,000 miles on the odometer and have put it to the test both on the rocks and on a 4,000 mile trek across America. After getting our faulty tach issue fixed, things had been running great and we've been real happy with the power we now have. It's far from being a rocket on the drag strip but holy cow do we ever have torque to spare. On the rocks, Moby will climb just about anything and with exceptional ease. On the highway, we now have plenty of passing power and still get better MPG than we did with our old 3.8L motor. Driving the speed limit on the highway, we can now get close to 14 MPG and around town or when playing with the skinny pedal, we don't get any worse than we were with the 3.8L which was about 10 MPG.
Now that summer is here, we've been pushing Moby hard to see just how well the new motor does in the heat and for the most part, the 2-pass Griffon radiator has been doing okay. Climbing long steep mountain passes, we have plenty of power but have to keep the AC off in order to prevent over heating. Even with the AC off, the factory temp gauge will still climb quite high if we keep the RPM at about 3k or higher. Going over Vail Pass in Colorado, the needle climbed all the way up to the 3/4 mark and it did have me concerned but, it did stop there and cooled off pretty quickly once we started to make our way back down. On one occasion, we even had our radiator purged some boiling water after the motor was stopped and after a long climb. At the time, the temp gauge didn't look hot but, with the motor off and the fan not blowing, I think things just heated up and gave a burp. Outside of that, so long as I keep the AC off when climbing on a hotter day, the radiator seems to do it job well enough. Not the perfect solution but, I suppose it was a bit of wishful thinking to think that we could keep a V8 cool with such a small radiator.
Speaking of AC, this is something that hasn't been working that well for us. To be clear, so long as we're driving and pushing 1000 RPM or more, it works fine if not on the nice and cold side but, at an idle or when descending a long hill, we get nothing but un-conditioned warm air blowing. Also, after driving 12 hours straight in 95+ temps, the AC just stopped blowing cold air. In fact, turning it off got it blowing cold for a bit again but nothing short of leaving it off for a while and then turning it back on about an hour later really fixed it.
In a nutshell, our new motor worked great in cooler weather and still works great so long as we're not climbing mountain passes on hot days but, I'll have to talk to Motech about this and see what they might recommend.
Otherwise, I will have to say that we're super happy with our new ProRock 80 and absolutely LOVE our new Atlas transfer case. For those of you who've never owned one, an Atlas is pricey but the gearing you can get and the options you have at your disposal are simply awesome! We've already used it several times to do front side burns and work our way through tough obstacles.
Anyway, if I think of anything else, I will be sure to post up about it here. Of course, if you have any questions, please let me know. :yup:
Now that summer is here, we've been pushing Moby hard to see just how well the new motor does in the heat and for the most part, the 2-pass Griffon radiator has been doing okay. Climbing long steep mountain passes, we have plenty of power but have to keep the AC off in order to prevent over heating. Even with the AC off, the factory temp gauge will still climb quite high if we keep the RPM at about 3k or higher. Going over Vail Pass in Colorado, the needle climbed all the way up to the 3/4 mark and it did have me concerned but, it did stop there and cooled off pretty quickly once we started to make our way back down. On one occasion, we even had our radiator purged some boiling water after the motor was stopped and after a long climb. At the time, the temp gauge didn't look hot but, with the motor off and the fan not blowing, I think things just heated up and gave a burp. Outside of that, so long as I keep the AC off when climbing on a hotter day, the radiator seems to do it job well enough. Not the perfect solution but, I suppose it was a bit of wishful thinking to think that we could keep a V8 cool with such a small radiator.
Speaking of AC, this is something that hasn't been working that well for us. To be clear, so long as we're driving and pushing 1000 RPM or more, it works fine if not on the nice and cold side but, at an idle or when descending a long hill, we get nothing but un-conditioned warm air blowing. Also, after driving 12 hours straight in 95+ temps, the AC just stopped blowing cold air. In fact, turning it off got it blowing cold for a bit again but nothing short of leaving it off for a while and then turning it back on about an hour later really fixed it.
In a nutshell, our new motor worked great in cooler weather and still works great so long as we're not climbing mountain passes on hot days but, I'll have to talk to Motech about this and see what they might recommend.
Otherwise, I will have to say that we're super happy with our new ProRock 80 and absolutely LOVE our new Atlas transfer case. For those of you who've never owned one, an Atlas is pricey but the gearing you can get and the options you have at your disposal are simply awesome! We've already used it several times to do front side burns and work our way through tough obstacles.
Anyway, if I think of anything else, I will be sure to post up about it here. Of course, if you have any questions, please let me know. :yup:
ttfhell
New member
Anything you would do different?
Well, even before we were finished with the swap, we had already been talking to Mel about things we might have to do to help cool things down. Being that all this was new and really, untested by anyone I know of who really uses their JK as hard as we do, we decided to try things out as is and see how things went. At this point and time, it's starting to look more and more like we're going to have to look into some of the cooling options Mel was talking about. But, I'll talk to Motech first to see if there's anything they can recommend.
OverlanderJK
Resident Smartass
Good to hear it's running relatively well. What's the cooling options, larger radiator? I thought you had the biggest that would fit?
Oh, it's running well and I'll be totally honest and say that we've been pushing it really hard on purpose. We do have the biggest and best radiator that we could get to fit but are still running our original factory 2007 fan with it. Mel is suggesting that we install a 2012-up fan as they apparently were designed to pull a lot more air through to help compensate for the heat a 3.6L puts out. Being that we haven't had any "overheating" issues, just getting warm to hot when pushed really hard, that's most likely where I'll start. Beyond that, a bigger radiator will be needed and some custom work will be needed to make that work.
Are you happy you went with LS swap over the Hemi..??
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Yes. As much as I like the idea of a HEMI, they still are way too big, don't fit unless you beat in your firewall, have significant overheating issues, get poor MPG and weigh a ton. The LS is still smaller, lighter, more fuel efficient and depending on how you do it, more affordable to do too. I still have tuning options that I can explore as well and that's something you just can't get with a HEMI.
Not exactly. The guys I know with HEMI's have serious overheating issues and that's with a jet turbine of a fan blowing all the time. Granted, I'm not thrilled by the fact that I am getting a warm to hot motor when driving fast and running the AC on long steep grades, I am still running the original 2007 fan and I have yet to actually overheat. I'm not real happy about my AC not working great either but hoping that Motech will have a solution for this. Either way, I will try the new fan first to address the heating issue and go from there.
Yes. We are running the recommended Griffon aluminum 2-pass radiator. Based on the rave reviews we had been hearing prior to buying the kit, I was hoping that we wouldn't have any issues with cooling but, what are you going to do. Clearly, all the guys who had been running this kit prior to us either tows their Jeep everywhere or live in areas where they are unable to really test them out.
jims68
New member
Eddie, Robbie eluded to he is working on something to get more of the air out of the engine Bay Area. Even with vented hoods the airflow is just not there! I built an aluminum shroud and seal to close off the intake area and even with the largest K&N filter I could fit in there it will start to heat sink after 90 degree temps. Can't imagine in your area what they are! The thermal dynamics of this front end just suck! Your air sounds like the condenser is freezing up. I want to update to his new control system which I think let's the jeep ECM handle the air again. I had a high and low cutout for air on mine but took out the low one. If I remember right the low one keeps the condenser from freezing up by cycling more often. The air conditioning guy I took it into couldn't see why it was needed so I took it out. Apparently only three wires under dash, stock cruise switch and no more CEL light for traction control! He has been hard to get a hold of lately. Really busy and I bet trying to catch up some. Sound like the Arabs have been swamping him last I spoke with him!
Patrfamilias
New member
AC issue
Tell me to shut-up if I'm being retarded, but have you checked your Freon level?
Tell me to shut-up if I'm being retarded, but have you checked your Freon level?
UtahJK
Member
There's a price list on the first page of this thread, so it looks like it was $650.
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Stegertime
Caught the Bug
:rock: Thats what I'm talking about, hand me downs!
RubiCAT will be getting an upgrade
SmokinV10
Caught the Bug
I've "heard" of some guys running big Hemi conversions that have an alleged 3 pass Ron Davis radiator. Would a better radiator fan coupled with a ventilated hood help? Would the additions of active fans to force air out of the ventilated hoods (the same way military vehicles vent air) potentially help? Have you looked into more efficient water pump options that move a higher volume of water and potential cooler thermostats?
Your real world experience and feedback is really helpful for me. Based on what I'm reading I'm "tapping the brakes" on my LS conversion since no AC is not an option in a constant 95 where + 80%+ humidity temps of Houston. With the humidity radiators are also less efficient.
Your real world experience and feedback is really helpful for me. Based on what I'm reading I'm "tapping the brakes" on my LS conversion since no AC is not an option in a constant 95 where + 80%+ humidity temps of Houston. With the humidity radiators are also less efficient.
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jims68
New member
SmokenV10 call Motech and talk to the guys there to get there latest kit updates and express your concerns and questions. Robbie can talk completely over ones head, just slow him down and be direct on your questions. I did the same finally with a few different kits Hemi's at first but kept going back to the LS conversion. The low cut off I was talking about is to help with freezing up the condenser by causing the compressor to cycle more. So far has not been needed in my area. That has all changed in his newer kits so ask on that also. Some of his UTube videos show LS conversions idling outside his shop in 110 plus temps, but this is under no heavy load either! I can't imagine how hot the LS7 conversions will get if pushed hard for any length of time! Maybe find out what else he is working on for cooling if you talk to him. My guess is he is trying to get the new 12+ fan to work with the old CanBus or other higher speed fan options.